Hollow pointing boolits to reduce weight to increase stability

[15meter]

As the title says, does reducing boolit weight help with stability?

I had problems with a 416 Rigby feeding with a rather blunt boolit so I had Accurate make me a mold that duplicated a factory profile bullet that feeds very well. Weight went up, being an all lead boolit. Fed like magic.

Stability went in the toilet, like flat out sideways on the target at 25-50 yards with very light loads(1200-1300 fps Trailboss load). If it even hit the 30"x30" piece of paper so we could see the perfect keyhole.

Sped the load up(1700+ with 5744), better but not great.

If you're still with me after the long winded explanation, would drilling a hole (hollow pointing) the boolit to reduce weight help with stability?

My google-fu is not particularly good today to do a search, too many cold/cough remedies in my system, so it's time to see if anybody else has an answer.

One rifle has a 16-1/2" twist second has 14". 14" twist is better but not awesome.

Would reducing the weight through hollow pointing help with stability, or should I stop trying to think?[smilie=b:

[megasupermagnum]

That's a big open ended question. I'll just say that I have found hollow points can often increase accuracy, at least in handguns. I don't think in my case it had anything to do with stability per se, I think it moved the center of gravity back, and just made them balance better. I believe this is why the most accurate bullet designs in handguns are often either SWC, or hollow point, they are better balanced. I've yet to find a round nose of any flavor be impressive.

Is there any reason you can't load the bullets you have any faster? The load data I'm seeing shows 416 rigby should have no problem sending a 400 grain bullet 2200-2500 fps. Ouch.

[15meter]

The OUCH is why.

Looking for dinger ringer loads that I can shoot a box or two without developing a lifetime flinch. @ 1700+ it still gets your attention.

Plus trying to avoid leading, did that with a 450 Nitro Express. ONCE.

[shortlegs]

The length of the bullet determines twist rate not the weight. Also if you have leading problems boolit size or alloy or lube could have caused leading. A lighter weight cast boolit of the right alloy with good lube would be pleasant to shoot.

[Larry Gibson]

The length of the bullet determines twist rate not the weight. Also if you have leading problems boolit size or alloy or lube could have caused leading. A lighter weight cast boolit of the right alloy with good lube would be pleasant to shoot.

^^^^^^^

Yup

[BrutalAB]

To add to this, the reason hollow points can help on stability is the boolit will be moving faster, thus achieving the higher rpm that the boolit needs to stabilize.

[GregLaROCHE]

Many competition jacked rifle bullets are hollow points. This is to reduce the weight in front of the main mass of the bullet. These bullets have a much greater length to width ratio than what you’re talking about, but this same principle may still improve stability in flat nosed bullets as well.

Nonetheless, you still need an adequate charge to stabilize any bullet. Also, if you go below minimum recommend charges, lower pressures may prevent the powder from burning correctly. That can result in varying muzzle velocity, therefore accuracy.

[USSR]

Many competition jacked rifle bullets are hollow points. This is to reduce the weight in front of the main mass of the bullet.

Not really. It is a result of having a more perfect bullet base by inserting the lead core from the front of the bullet jacket instead of the rear. The bullet base is much more critical for accuracy than the bullet tip.

Don

[Larry Gibson]

15meter

What is the length of the bullet, with GC, that you are using?

[GregLaROCHE]

Not really. It is a result of having a more perfect bullet base by inserting the lead core from the front of the bullet jacket instead of the rear. The bullet base is much more critical for accuracy than the bullet tip.

Don

Sorry to disagree, but if more of the mass is consolidated at the center of the bulle, it will be more stable. Maybe some others will help me out with more details.

[bmortell]

it sounds like you have a longer projectile since you said you went from a blunt bullet that don't feed well to something more like factory rounds. but no id think hollow pointing it would just keep the same length with a more rear heavy balance and be harder to stabilize. if anything you want to hollow point the rear end so it stabilizes easy like a foster slug or minieball.

id just make sure the diameter is good and try harder lead to see if its more stable, if not rpm stability for that length is whats left, so you need more speed and rpm's. making them hollow base for shuttlecock effect should help on paper but not realistically something id want to do.

for the jacketed accuracy/balance thing I don't think that has to do with balance there just shape optimized for drag, there natural balance is backwards.

[15meter]

This was basically a duplication of a good shooting jacketed bullet in cast. I sent Accurate a jacketed bullet that feeds very well and shot great. I asked him to duplicate it in a g/c cast boolit. The mold casts a beautiful slug that weighs 384 grains.

Overall length is 1.245, I was hoping that a hollow pointing job would let me keep the speed down, reducing the OUCH factor.

[bmortell]

well technically hollow pointing the nose would reduce weight which helps recoil, but youd have to still increase the speed for the stability which increases recoil. and if its a more pointed aerodynamic shape you cant effectively remove very much weight cause the nose isn't that wide. so overall its probably not that efficient at solving your problem. normally id say just keep that mold for high power loads and get a lighter weight cheap mold for low speed loads but 42 cal isn't common so sticky situation

[country gent]

I believe you are right at the edge. With increasing the velocity making it better. When the all copper bullets first came out the standard weights for caliber shot poor due to added length. For what your wanting a bullet in the 1.1" range should be very close. What you might try with your existing bullet is to cut the first band and grease groove off. shortening the bullet probably about .100 and test.
If you have a case trimmer with collet to hold the bullet it can be done there. or with a couple pieces of hard wood clamp together drill 2 dowel holes thru sides. Then in a vise drill a bullet dia sized hole to correct depth. you want the hole size for size or a couple thousandths smaller. When you drill this hole have e pieces of index card between them to provide a small gap to allow clamoing pressure.

In use set in vise. drop bullet into hole resting on bottom. clamp with vise. With a fine blade hack saw or jeweler's saw cut bottom off and file flat to fixture. Make a group to load some test ammo. IM betting the shorter length will make them better.

A small lathe with collets and a collet stop would make this easy to do in one pass. set bullet into collet against stop. Use a cut off blade and cut to length. Lock carriage down in place or set a stop for it.

Hollow pointing will lighten the bullet but wont change the length. Cutting the nose back changes the working profile you want / need. Make a cou[le extras so if they work you can send them to the mould maker to show what you need. Or you may be able to cut the blocks down that much also

[megasupermagnum]

This was basically a duplication of a good shooting jacketed bullet in cast. I sent Accurate a jacketed bullet that feeds very well and shot great. I asked him to duplicate it in a g/c cast boolit. The mold casts a beautiful slug that weighs 384 grains.

Overall length is 1.245, I was hoping that a hollow pointing job would let me keep the speed down, reducing the OUCH factor.

I don't see the exact bullet based on that. Is there any chance it is the #42-365S ? I don't put much faith in the bullet stability calculators, but I tried three online, and all three say that should be more than stable, even with the 16.5" twist at 1200 fps.

I would think it better to start at the basics first. Bullet fit being #1. This forum is littered with people who had tumbling bullets that turned out to be undersized.

[15meter]

I don't see the exact bullet based on that. Is there any chance it is the #42-365S ? I don't put much faith in the bullet stability calculators, but I tried three online, and all three say that should be more than stable, even with the 16.5" twist at 1200 fps.

I would think it better to start at the basics first. Bullet fit being #1. This forum is littered with people who had tumbling bullets that turned out to be undersized.

That's the mold I had Accurate design, it measures 1.245" with g/c. It really is a nice boolit, and it feeds perfectly.

I have not and will not slug the bore of this rifle, it's a friend's custom rifle that cost more than my last truck:holysheep.

May try pan lubing some as cast, don't remember the as cast size and don't have any that haven't been sized.

The pot is on the bench and I got the mold out yesterday, may be the new year's Eve project.

What old geezers do for excitement:2 drunk buddies:

[USSR]

Here's a good article regarding the differences between full metal jacket bullets and hollow point rifle bullets, and the importance of the bullet base: https://www.ssusa.org/articles/2018/8/19/why-are-hollow-point-rifle-bullets-more-accurate/

Don

[Larry Gibson]

That's the mold I had Accurate design, it measures 1.245" with g/c. It really is a nice boolit, and it feeds perfectly.

I have not and will not slug the bore of this rifle, it's a friend's custom rifle that cost more than my last truck:holysheep.

May try pan lubing some as cast, don't remember the as cast size and don't have any that haven't been sized.

The pot is on the bench and I got the mold out yesterday, may be the new year's Eve project.

What old geezers do for excitement:2 drunk buddies:

What size do the bullets drop at?

What are you sizing at?

Lube or PC?

[Bent Ramrod]

I have a .44 paper-patch mould that casting at 500+ gr was too long for the twist in my rifle. I had read that the Canadian blackpowder shooters used hollowpoint cast boolits for extra stability at long range (this in the 80s) so I drilled holes of various depths in the noses to see if they flew with less yaw. It’s written up in the BP paper patch section. IIRC, I might have had fewer oval holes in strings of 5 at the Pig and Turkey lines, but the treatment didn’t totally eliminate them.

Still have 50 of the overlong boolits; too many other projects have delayed getting back to the experiment. Drilling holes in lead is pretty tedious, too.

[swheeler]

As the title says, does reducing boolit weight help with stability?

I had problems with a 416 Rigby feeding with a rather blunt boolit so I had Accurate make me a mold that duplicated a factory profile bullet that feeds very well. Weight went up, being an all lead boolit. Fed like magic.

Stability went in the toilet, like flat out sideways on the target at 25-50 yards with very light loads(1200-1300 fps Trailboss load). If it even hit the 30"x30" piece of paper so we could see the perfect keyhole.

Sped the load up(1700+ with 5744), better but not great.

If you're still with me after the long winded explanation, would drilling a hole (hollow pointing) the boolit to reduce weight help with stability?

My google-fu is not particularly good today to do a search, too many cold/cough remedies in my system, so it's time to see if anybody else has an answer.

One rifle has a 16-1/2" twist second has 14". 14" twist is better but not awesome.

Would reducing the weight through hollow pointing help with stability, or should I stop trying to think?[smilie=b:

Your bullets should be stable in either barrel sub sonic. Sideways at 25 yds you must be leaded up to smoothbore status:idea:

[mdi]

I have absolutely no experience with any Riby cartridge but I did stay at a Motel 6 last night. Seriously, I have cast/shot a bunch of rifle bullets and after reading the OP, my first inclination would be to check bullet to gun fit first. The old "slug the barrel and mike the bullets" method. ;-)

[swheeler]

Yep, but now that those undersized bullets have been shot, "mine the lead!" ........:oops:

[15meter]

I have absolutely no experience with any Riby cartridge but I did stay at a Motel 6 last night. Seriously, I have cast/shot a bunch of rifle bullets and after reading the OP, my first inclination would be to check bullet to gun fit first. The old "slug the barrel and mike the bullets" method. ;-)

No leading in the barrel, and apparently you missed my post about NOT slugging a buddies very high dollar custom rifle.

He paid more for this rifle than I paid for my last truck[smilie=1:

I'd post a photo of the rifle but I did something to my computer in the settings that won't let me. When I figure out what security setting I changed, I'll post a photo of it.

It's waaaay to purty to come near it with a lead slug and a hammer.

[Larry Gibson]

Let me ask again;

What size do the bullets drop at?

What are you sizing at?

Lube or PC?

[15meter]

Let me ask again;

What size do the bullets drop at?

What are you sizing at?

Lube or PC?

Sorry,

I thought I had posted that I don't know the as cast dia. because I don't currently have any that haven't been sized. Was going to cast some this evening but this head cold/sinus infection/bronchitis/creeping crud that has been dragging me down since December 1st is back.

Sized size is 418, standard commercial lube, (Lyman) with a gas check.

May cast some tomorrow if I can quit coughing and sneezing long enough. Last night was the first night in a month I got more than 5 hours of sleep.

[GregLaROCHE]

If you sent a jacketed bullet for a mold the same size, did the manufacturer take into account that cast boolits normally need to be larger than jacketed? If your boolits measure the same as the jacketed, they could be too small. Something that can remedied.

Also I don’t see any reason slugging the barrel could harm the gun. You need pure soft lead and a rod that is softer or plastic coated to drive the slug down. I use a steel rod with electrical shrink wrap on it. Otherwise, brass will work and make a collar out of wood or plastic to center it at the muzzle to be really sure. Of course, ask your friend first, but if he knows all the facts, he probably won’t object.

[charlie b]

FWIW, 1100-1200 may put you in the transonic range. This is one of the speed ranges that some bullets just don't like and react badly. I suspect that is the reason your accuracy improves a bit above those speeds. If you are trying to avoid recoil then go slower, around 1000fps and see what happens (after you make sure the bullets fit the bore). If you want a hunting round then go up to 1500fps or more.

For fitting cast I go in from the chamber side with an oversize slug. Two reasons. First, some barrels are a bit smaller at the muzzle than at the breach and I want the bullet to fit at the throat. Second, I want to see how long and what dia the throat is as well.

For the slug I can usually get away with a cast bullet, even a sized one. Put it in the vise lengthwise and crush it a bit until the dia is larger than the throat. Then pound it in from the back just far enough to fully engrave the rifling. I use a punch that is closer to bullet dia (with tape around it). A taped cleaning rod is used from the muzzle to tap it out (takes very little force to get it out).

[mdi]

No leading in the barrel, and apparently you missed my post about NOT slugging a buddies very high dollar custom rifle.

He paid more for this rifle than I paid for my last truck[smilie=1:

I'd post a photo of the rifle but I did something to my computer in the settings that won't let me. When I figure out what security setting I changed, I'll post a photo of it.

It's waaaay to purty to come near it with a lead slug and a hammer.

Well, without using proven methods, it's all a WAG...

[15meter]

If you sent a jacketed bullet for a mold the same size, did the manufacturer take into account that cast boolits normally need to be larger than jacketed? If your boolits measure the same as the jacketed, they could be too small. Something that can remedied.

Also I don’t see any reason slugging the barrel could harm the gun. You need pure soft lead and a rod that is softer or plastic coated to drive the slug down. I use a steel rod with electrical shrink wrap on it. Otherwise, brass will work and make a collar out of wood or plastic to center it at the muzzle to be really sure. Of course, ask your friend first, but if he knows all the facts, he probably won’t object.


Both Accurate and I am smart enough to spec and make a mold that is larger than standard jacket bullet diameter for cast use, it was spec'ed at .418 and cast very close to that or a little larger.

I Beagled the mold today and cast some at ~ .421 to try as pan lubed boolits.

The mold is:

http://www.accuratemolds.com/bullet_detail.php?bullet=42-365S-D.png

I slugged one of the bores of another of my buddie's rifles, I thought he was going to stroke out. Not going to do that again. Lost 2 buddies last year, have one in hospice and another that will probably be there fairly shortly. Don't need to lose any more.

Just keep playing up and down with speed/diameter. May still hollow point some, I have a lathe with collets, not like it's a real tough machining operation, may just for grins, drill some from the back before the g/c goes on. Retired guy with a nice shop to keep me out from under the wife's feet.

Plus no ice to go sailing with the buddies that are still kicking.

Might as well make weirdness in the shop.